74 Natural History of British Zoophytes. 
ture the tenements and products of animals similar in many respects 
to the naked fresh-water polype. By examining them, in a living 
state, through an ordinary microscope, he saw these polypes in the 
denticles or cells of the zoophyte ; he witnessed them display their 
tenacula for the capture of their prey, their varied actions and 
sensibility to external impressions, and their mode of propagation ; 
he saw further that the little creatures were organically connected 
with the cells and could not remove from them, and that although 
each cell was appropriated to a single individual, yet was this unit- 
ed " by a tender thready line, to the fleshy part that occupies the 
middle of the whole coralline," and in this manner connected with 
all the individuals of that coralline. The conclusion was irresisti- 
ble the presumed plant was the skin or covering of a sort of mini- 
ature hydra, a conclusion which Ellis strengthened by an exami- 
nation of the covering separately, which, he said, was as much an 
animal structure as the nails or horns of beasts, or the shell of the 
tortoise, for it differs from " sea-plants in texture, as well as hard- 
ness, and likewise in their chemical productions. For sea-plants, 
properly so called, such as the Algae, Fuci, &c. afford in distillation 
little or no traces of a volatile salt : whereas all the corallines afford 
a considerable quantity ; and in burning yield a smell somewhat re- 
sembling that of burnt horn, and other animal substances ; which 
of itself is a proof that this class of bodies, though it has the vegeta- 
ble form, yet is not entirely of a vegetable nature."* 
Ellis taught no novel doctrine, but he gave it fixidity and curren- 
cy ; and he moreover applied it to those very zoophytes which pos- 
sessed the vegetable appearance in the most perfection, many of 
which he was the first to notice, and which he illustrated with a se- 
ries of figures of unequalled accuracy.t He rarely went beyond the 
* Dr Good is in error when he states that the ammoniacal smell from burnt 
zoophytes was the principal fact forplacing them in the animal kingdom Book 
of Nature, i. 175 and 210. 
f As mentioned above, Bernard de Jussieu knew that the Sertulariadae the 
zoophytes here alluded to were animal productions, but no detailed account of 
his observations seems ever to have been published. Trembley had made the 
same discovery. Dr Watson, in his account of Peyssonnel's treatise in 1752, 
tells us that Mr Trembley shewed him, " at the late excellent Duke of Rich- 
mond's," the small white polypes of the Corallina minus ramosa alterna vice den- 
ticulata of Ray, " exactly in form resembling the fresh- water polype, but infinite- 
ly less." " When the water was still, these animals came forth, and moved their 
claws-in search of their prey in various directions ; but, upon the least motion 
of the glass, they instantly disappeared." P. 463 Linnaeus, however, in refer- 
ence to the observations made previous to Ellis, says they are " inchoatae, non 
ad plenum confectae, et desiderentur adhuc quam plurima, quae dies forte reve- 
labit." Amoen. Acad. vol. i. p. 186. 
